Reverse Linked List
123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154
/*
What is the linked lists
[5] [10] [2]
head tail => null
*/
const basket = ['apples','grapes','pears'];
/*
linked list : apples --> grapes --> pears
prepend O(1)
append O(1)
lookup O(n)
insert O(n)
delete O(n)
We need to understand about the LinkedList
*/
/* how object will work in the javascript and pointer
pointer is the reference in the memory.
*/
const obj1 = {a : true};
const obj2 = obj1;
obj1.a = 'booya';
console.log('1', obj1);
console.log('2',obj2);
/*
Very first link list data structure.
10 --> 5 --> 16
*/
/*let myLinkedList = {
head: {
value : 10,
next: {
value : 5,
next: {
value : 16,
next : null
}
}
}
}*/
class LinkedList{
constructor(value){
this.head = {
value : value,
next: null
}
this.tail = this.head;
this.length = 1;
}
append(value)
{
//code here
const newNode = {
value :value ,
next : null
};
this.tail.next = newNode;
this.tail = newNode;
this.length++;
return this;
}
prepend(value){
const newNode = {
value :value ,
next : null
};
newNode.next = this.head;
this.head = newNode;
this.length++;
return this;
}
insert(index, value){
//check my parameter
if(index >= this.length)
{
return this.append(value);
}
const newNode ={
value : value,
next : null
};
const leader = this.traverseToIndex(index-1);
const holdingPointer = leader.next;
leader.next = newNode;
newNode.next = holdingPointer;
this.length++;
return this.printList();
}
traverseToIndex(index)
{
//check params
let counter= 0 ;
let currentNode = this.head;
while(counter !== index)
{
currentNode = currentNode.next;
counter++;
}
return currentNode;
}
printList(){
const array = [];
let currentNode = this.head;
while(currentNode !== null )
{
array.push(currentNode.value);
currentNode = currentNode.next;
}
return array;
}
remove(index){
//check params
const leader = this.traverseToIndex(index-1);
const unWantedNode = leader.next;
leader.next = unWantedNode.next;
this.length--;
return this.printList();
}
reverse(){
if(!this.head.next){
return this.head;
}
let first = this.head;
this.tail = this.head;
let second = first.next;
while(second){
const temp = second.next;
second.next = first;
first = second;
second = temp;
}
this.head.next = null;
this.head = first;
return this;
}
}
const myLinkedList = new LinkedList(10);
myLinkedList.append(5);
myLinkedList.append(16);
myLinkedList.prepend(1);
myLinkedList.insert(3,44);
//myLinkedList.remove(2);
console.log(myLinkedList.printList());
myLinkedList.reverse();
console.log(myLinkedList.printList());
JavaScript
INFO